Case Study: Grounding Issues with Solutions

This case study is a result of an NLSI client audit in southeastern United States.
Lightning-caused damages to sensitive electronic equipment were traced to resistive soils.
Architects and engineers had specified
typical NEC 250 grounding designs. They were inadequate.

3. Conclusion.
Native "grounds" are composed of highly resistive sandy soils. This poor earthing defeats a direct and preferential path for lightning. As a result, lightning follows other (many) pathways of lesser impedance through equipment.

4. Remedy.
Non-native engineered products (backfills) or salt-treatment of existing soils are the only options to reduce high impedance grounds. Driving additional ground rods will not increase volume of the earth electrode in any meaningful way.
Conductive cement is preferred over "chemical ground rods" due to sand porosity
which may dilute the effectiveness of soils conditioning.